【摘要】：以CO2（R744）與“零ODP”、“低GWP”人工制冷劑組成的混合制冷劑為研究內(nèi)容，揚長避短，發(fā)揮制冷劑各自的優(yōu)勢，提高CO2系統(tǒng)效率，降低CO2系統(tǒng)排氣壓力，減小人工制冷劑充灌量和可燃性。采用理論分析和實驗研究相結(jié)合的研究方法，以CO2水-水熱泵系統(tǒng)實驗臺和制冷劑燃燒極限測試實驗臺為基礎(chǔ)，研究混合制冷劑的燃燒特性、添加劑對CO2水-水熱泵系統(tǒng)性能的影響及用CO2混合制冷劑的熱泵系統(tǒng)性能。 以R744/R32混合制冷劑為重點，分析R744/R32、R744/R41和R744/R161混合制冷劑的物性參數(shù)，將NIST混合制冷劑參數(shù)與實驗數(shù)據(jù)對比分析，采用Helmholtz狀態(tài)方程對R744/R32混合制冷劑參數(shù)進行了優(yōu)化，優(yōu)化后的最大誤差由6%降低到3.4%，計算精度顯著提高。 對R744/R32，R744/R41，R744/R161，R744/R152a，R744/R290和R744/R1270共6組混合制冷劑進行熱力學理論分析。當CO2的質(zhì)量分數(shù)高于0.95時，循環(huán)為跨臨界循環(huán)；隨著CO2含量的降低，當CO2的質(zhì)量分數(shù)低于0.95時，循環(huán)由跨臨界循環(huán)過渡到亞臨界循環(huán)。純CO2以及CO2混合制冷劑的熱泵循環(huán)存在最大COP及對應(yīng)的最優(yōu)排氣壓力。當CO2質(zhì)量分數(shù)小于0.85時，R744/R32的系統(tǒng)效率最大，CO2質(zhì)量分數(shù)大于0.85時，R744/R161的系統(tǒng)效率最大。 對R744/R32、R744/R41和R744/R161混合制冷劑燃燒下限（LFL）進行實驗研究，分析惰性氣體對燃燒下限（LFL）的影響，結(jié)果表明：隨著CO2含量的增加燃燒下限（LFL）逐漸升高。當混合制冷劑中CO2的體積比接近50%時，與純質(zhì)的R32、R41和R161相比，燃燒下限（LFL）分別提高了0.5%、0.4%和0.45%。 基于跨臨界CO2水-水熱泵實驗臺，在充灌量一定的基礎(chǔ)上，對含R32、R41和R161三種添加劑（添加劑質(zhì)量分數(shù)小于5%）的跨臨界CO2水-水熱泵系統(tǒng)及R32添加劑對膨脹機的影響進行實驗研究，對CO2水-水熱泵系統(tǒng)用R744/R32，R744/R41，R744/R161三種混合制冷劑（R32、R41和R161質(zhì)量分數(shù)5～50%）的性能進行實驗研究。研究結(jié)果表明： 添加R32、R41和R161添加劑后，在部分工況下，COPh和COPc明顯提高，COPh和COPc提高幅度R32R161R41。 在CO2水-水熱泵系統(tǒng)用R744/R32，R744/R41，R744/R161三種混合制冷劑中，制熱工況下，推薦使用R744/R32和R744/R41組成的混合制冷劑，最大COPh時，R32含量和R41含量分別為50%和40%，與純質(zhì)CO2相比，COPh對應(yīng)提高20.4%和11.9%。制冷工況下，推薦使用R744/R32和R744/R41混合制冷劑，，最大COPc時，R32含量和R41含量分別為40%和40%，與純質(zhì)CO2相比，COPc對應(yīng)提高20.8%和18.5%。R744/R32和R744/R41混合制冷劑隨著R32和R41含量的增加，排氣壓力顯著降低，與純質(zhì)CO2相比，R744/R32混合制冷劑的排氣壓力最大降低幅度達37.9%，R744/R41混合制冷劑的排氣壓力最大降低幅度達15%。由于滑移溫度過大，制熱量和制冷量顯著減小，不推薦使用R744/R161混合制冷劑。
[Abstract]:The mixed refrigerants composed of CO2 (R744), "zero ODP" and "low GWP" artificial refrigerants are taken as the research content. The advantages and disadvantages of the refrigerants are given full play to improve the efficiency of the CO2 system and reduce the exhaust pressure of the CO2 system. Reduce the filling amount and flammability of artificial refrigerants. The combustion characteristics of mixed refrigerants were studied by using the combination of theoretical analysis and experimental research, based on the CO2 water-water heat pump system test bench and the refrigerants combustion limit test bench. The effect of additives on the performance of CO2 water-water heat pump system and the performance of heat pump system with CO2 mixed refrigerants. With emphasis on R744/R32 mixed refrigerants, the physical parameters of R744 / R32, R744 / R41 and R744/R161 mixed refrigerants are analyzed, and the parameters of NIST mixed refrigerants are compared with the experimental data. The Helmholtz equation of state is used to optimize the parameters of R744/R32 mixed refrigerants. The maximum error is reduced from 6% to 3.4%, and the calculation accuracy is significantly improved. Thermodynamic theoretical analysis of six groups of mixed refrigerants, R744 R42, R744 R161, R744 R152A, R744 R290 and R744/R1270, was carried out for R744 R32, R744 R41, R744 R161, R744 R152A, R744 R290 and R744 R290. When the mass fraction of CO2 is higher than 0.95, the cycle is transcritical cycle, and with the decrease of CO2 content, when the mass fraction of CO2 is less than 0.95, the cycle changes from transcritical cycle to subcritical cycle. The heat pump cycle with pure CO2 and CO2 mixed refrigerants has the maximum COP and the corresponding optimal exhaust pressure. When the mass fraction of CO2 is less than 0.85, the system efficiency of R744/R32 is the highest, and when the mass fraction of CO2 is greater than 0.85, the system efficiency of R744/R161 is the highest. The combustion lower limit (LFL) of R744 / R32, R744 / R41 and R744/R161 mixed refrigerants was studied experimentally. the effect of noble gas on the combustion lower limit (LFL) was analyzed. The results show that the combustion lower limit (LFL) increases gradually with the increase of CO2 content. When the volume ratio of CO2 in the mixed refrigerants is close to 50%, compared with the pure R32, R41 and R161, the combustion lower limit (LFL) is increased by 0.5%, 0.4% and 0.45%, respectively. Based on the transcritical CO2 water-water heat pump experimental platform, on the basis of a certain amount of filling, the content of R32, The transcritical CO2 water-water heat pump system with R41 and R161 additives (the mass fraction of additives is less than 5%) and the effect of R32 additives on the expander were studied experimentally. the R744 鈮

本文編號：2479887